Systemic lupus erythematosus (SLE) is an autoimmune disorder of largely unknown etiology characterized by profound effector T cell dysfunction. Infection-related morbidity and mortality rates are high among patients with SLE and although multifactorial it has been attributed to disease activity, the use of immunosuppressive drugs and deficient cell-mediated cytotoxic responses that are associated with decreased expression of interleukin (IL)-2. IL-17 production on the other hand is increased in SLE patients and mice and IL17-producing cells invade the kidney in patients with lupus nephritis. cAMP response element modulator (CREM)? has been claimed to suppress the production of IL-2 through transcriptional and epigenetic mechanisms and to promote the production of IL-17 through epigenetic modulation. It is postulated herein that CREM? effects transcriptional and epigenetic modifications which account for the antithetic expression of IL2 and IL-17 and the subsequent disease expression in patients with SLE and lupus- prone mice and that silencing it should have a clinical benefit. Accordingly, experiments are proposed to understand the CREM? -mediated transcriptional and epigenetic mechanisms that are involved in the control of expression of IL-2 and IL-17 in SLE and the distribution of IL-17-producing cells in tissues, to establish the role of CREM? in the regulation of autoimmunity and lupus-related pathology in mice and to treat lupus-prone mice with an inducible IL-2 gene expression system and by silencing CREM?. The proposed work using novel concepts (epigenetic control of cytokine production) and novel, genetically modified, mice intends to clarify central mechanisms in the pathogenesis of SLE and to introduce infusion of IL-2 or silencing of CREM as new treatments for SLE.